The invention relates to a method and system for utilizing alcohol and gasoline separately and simultaneously in an internal combustion engine in a manner which eliminates the problems in the production, supplying, and utilization of these fuels in a blended configuration.
Automotive fuels commonly used in the United States are gasoline, diesel oil, and recently gasohol, a fuel blend of anhydrous ethyl alcohol (ethanol, 200 proof) and gasoline (lead free) normally found in a ratio of ten percent alcohol and ninety percent gasoline. However, there are certain problematic restrictions, both technical and economical in the production and use of gasohol. More than ten percent of two hundred proof ethanol in the gasohol blend causes phase separation in the fuel tank resulting in the separation of the gasoline and alcohol into two immiscible layers. The use of a lesser grade of alcohol, in any amount, such as 190 proof (containing five percent water) or 180 proof alcohol (containing ten percent water) will also cause phase separation.
Because 200 proof ethyl alcohol is very hygroscopic it attracts water or moisture from the atmosphere and thereby becomes less than 200 proof which, especially at low temperatures, causes the phase separation in the fuel tank. While certain additives may be added to the gasohol blend in order to inhibit phase separation, these chemicals are expensive and may act as pollutants or ignition retardants. The blending operation involved in the production of gasohol has to be performed under conditions which exclude the possibility of water or moisture absorption. This increases the cost of gasohol. When storing or transporting gasohol similar precautions must be taken in order to avoid moisture absorption.
Operational commercial grades of ethyl alcohol (180-190 proof) can be produced easily at atmospheric pressure. However, rectifying this grade of alcohol to make it two hundred proof is expensive as the last trace of water is not easily removed. Therefore, if 180-190 proof ethyl alcohol could be used as a fuel grade alcohol cost savings at the levels of production, handling, and use would accrue.
Attempts to remedy some of the above mentioned problems have been made such as in U.S. Pat. No. 4,019,477 wherein a system is disclosed for supplying an internal combustion engine with different fuels under different loads. A separate tank for gasoline fuel and for alcohol fuel is provided and an auxiliary carburetor meters the alcohol fuel in relation to engine load. However, the alcohol fuel is arranged to provide a substantial portion of the required fuel-air mixture only under idle and low loads and the gasoline is utilized under high load conditions. Mixture of the fuels occurs in an atomized phase but no emphasis is given vaporization of the alcohol.
In U.S. Pat. No. 4,031,864 a system is disclosed for utilizing multiple fuels in an internal combustion engine wherein a single fuel tank is employed in which phase separation of a gasoline/ethanol blend is induced by the addition of water. Means are provided for supplying the fuels separately and utilizing them in predetermined ratios in the general combustion engine. Thus, the problems of producing and supplying a blend of gasoline and alcohol to the motorist are still encountered. Furthermore, problems are encountered with maintaining the different fuels in separate layers in the fuel tank during operation of vehicles and preventing them from mixing due to agitation when the automobile is in motion. Such agitation causes the separated fuel components and water to form a fairly coarse, rather non-uniform and unstable emulsion impairing normal operation of the engine.
Accordingly, an important object of the present invention is to provide a system and method for reducing the problems and the cost of the production, handling, and usage of alcohol fuels in motor vehicles.